Marta Kostyuk enters as the clear favorite against Sloane Stephens at the US Open, backed by her No. 11 ranking, career-high form, and 33-8 record in 2026 that includes semifinals at Roland Garros and Wimbledon plus a recent straight-sets win over Stephens in Cincinnati. The Ukrainian has compiled strong hard-court results this season and holds serve efficiently while converting break opportunities at a high rate. Stephens, a former US Open champion, has climbed from outside the top 700 to around No. 240 through a wild-card run that produced consecutive wins in Cincinnati, but she remains well below her peak level after extended injury absences and faces a significant step up in class on outdoor hard courts. Head-to-head history is limited, yet recent momentum and ranking disparity shape trader consensus around Kostyuk advancing.
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Marta Kostyuk – Sloane Stephens
Moneyline
$0 Vol.
Game Spread
$0 Vol.
This market will resolve to 'Marta Kostyuk' if Marta Kostyuk advances against Sloane Stephens.
This market will resolve to 'Sloane Stephens' if Sloane Stephens advances against Marta Kostyuk.
If the match is canceled (not played at all), ends in a tie, or a winner has not been determined by September 16, 2026, 11:59 PM ET (14 days after the scheduled start), this market will resolve to 50-50.
If the match begins but is not completed, and one player advances due to the opponent's retirement, default, or disqualification, this market will resolve to the player who advances.
If the match ends in a walkover (player withdraws before the start and the other advances automatically), this market will resolve to 50-50.
The primary resolution source will be official information from the WTA Tour. A consensus of credible reporting may also be used.
Market Opened: Sep 1, 2026, 12:14 AM ET
Resolution Source
https://www.wtatennis.com/scoresResolver
0x65070BE91...Marta Kostyuk – Sloane Stephens
Moneyline
$0 Vol.
Game Spread
$0 Vol.
This market will resolve to 'Marta Kostyuk' if Marta Kostyuk advances against Sloane Stephens.
This market will resolve to 'Sloane Stephens' if Sloane Stephens advances against Marta Kostyuk.
If the match is canceled (not played at all), ends in a tie, or a winner has not been determined by September 16, 2026, 11:59 PM ET (14 days after the scheduled start), this market will resolve to 50-50.
If the match begins but is not completed, and one player advances due to the opponent's retirement, default, or disqualification, this market will resolve to the player who advances.
If the match ends in a walkover (player withdraws before the start and the other advances automatically), this market will resolve to 50-50.
The primary resolution source will be official information from the WTA Tour. A consensus of credible reporting may also be used.
Market Opened: Sep 1, 2026, 12:14 AM ET
Resolution Source
https://www.wtatennis.com/scoresResolver
0x65070BE91...Marta Kostyuk enters as the clear favorite against Sloane Stephens at the US Open, backed by her No. 11 ranking, career-high form, and 33-8 record in 2026 that includes semifinals at Roland Garros and Wimbledon plus a recent straight-sets win over Stephens in Cincinnati. The Ukrainian has compiled strong hard-court results this season and holds serve efficiently while converting break opportunities at a high rate. Stephens, a former US Open champion, has climbed from outside the top 700 to around No. 240 through a wild-card run that produced consecutive wins in Cincinnati, but she remains well below her peak level after extended injury absences and faces a significant step up in class on outdoor hard courts. Head-to-head history is limited, yet recent momentum and ranking disparity shape trader consensus around Kostyuk advancing.
Experimental AI-generated summary referencing Polymarket data. This is not trading advice and plays no role in how this market resolves. · UpdatedBeware of external links.
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